WO2020241447A1

WO2020241447A1 - Update device, update method, update program, and data structure

Info

Publication number: WO2020241447A1
Application number: PCT/JP2020/020133
Authority: WO
Inventors: 盛徳大橋; 滋藤村; 達郎石田; 篤中平; 大喜渡邊; 岸上　順一
Original assignee: 日本電信電話株式会社
Priority date: 2019-05-29
Filing date: 2020-05-21
Publication date: 2020-12-03
Also published as: US20220253230A1; JP7333554B2; JP2020194385A

Abstract

According to the present invention, when a file after update, which is obtained after an original file is updated, is registered to a distributed file management system 100, a difference creation unit 222 creates a difference file between the original file and the file after update, a route object creation unit 223 creates a route object including an ID of the original file and an ID of the difference file, and a distributed file management client 11 registers the difference file and the route object to the distributed file management system 100.

Description

Update device, update method, update program, and data structure

The present invention relates to a technique for updating a file managed by a distributed file management system.

IPFS (InterPlanetary File System) is known as a decentralized distributed file management system (Non-Patent Document 1). In IPFS, files are divided into chunks of a certain size and managed by terminals belonging to IPFS. Each chunk is given an ID generated from the hash value. Chunks that make up the same file are organized in a tree. The root chunk contains links to each chunk that makes up the file. The ID of the chunk that is the root becomes the ID that indicates the file. The number of divisions is determined by the chunk setting size and file size. If the chunk size is larger than the file size, the file will not be split. Here, it is expressed as a chunk even if it is not divided.

The blockchain has extremely strong resistance to tampering. Focusing on this point, it is conceivable that the blockchain and the distributed file management system will be linked. When linking the blockchain and the distributed file management system, the distributed file management system needs to keep not only the updated file but also the unupdated file as a record.

However, the method of newly registering the updated file in the distributed file management system has a problem that the file capacity managed by the entire system becomes large.

The present invention has been made in view of the above, and an object of the present invention is to reduce the average file size per file managed by the entire file system.

The update device of one aspect of the present invention is an update device that registers an update file that updates the original file registered in the distributed file management system in the distributed file management system, and is a difference between the original file and the update file. A difference generation unit that generates data, a route object generation unit that generates a route object including a link to the original file and a link to the difference data, and the difference data and the root object are registered in the distributed file management system. It is characterized in that it is provided with a file management control unit.

The update method of one aspect of the present invention is an update method by an update device that registers an update file that updates the original file registered in the distributed file management system in the distributed file management system, and the original file and the update file. A step of generating the difference data with the file, a step of generating a root object including a link to the original file and a link to the difference data, and a step of registering the difference data and the root object in the distributed file management system. And, characterized by having.

The data structure of one aspect of the present invention is a data structure of an update file obtained by updating the original file, and includes a link to the original file and a link to the difference data between the original file and the update file. If the source file is another update file, the link to the source file is a link to the data structure of the other update file, and the computer will take the source file from the link to the source file. It is used in the process of acquiring, acquiring the difference data from the link to the difference data, applying the difference data to the original file, and acquiring the update file, and the link to the original file is the other update. If it is a link to a data structure to a file, the computer is characterized by recursively processing the data structure of the other update file.

According to the present invention, the average file size per file managed by the entire file system can be reduced.

FIG. 1 is a diagram showing an overall configuration of the distributed file management system of the first embodiment. FIG. 2 is a diagram for explaining the configuration of files managed by the distributed file management system of the first embodiment. FIG. 3 is a diagram showing an example of the data structure of the root object. FIG. 4 is a diagram showing an example of a data structure managed by the distributed file management system of the first embodiment. FIG. 5 is a diagram showing a configuration of a creator terminal and an updater terminal of the distributed file management system of the first embodiment. FIG. 6 is a sequence diagram showing a flow of processing for registering the file generated in the first embodiment. FIG. 7 is a sequence diagram showing a flow of processing for registering the updated file in the first embodiment. FIG. 8 is a diagram showing the overall configuration of the distributed file management system and the blockchain system of the second embodiment. FIG. 9 is a diagram showing an example of a data structure managed by the distributed file management system of the second embodiment. FIG. 10 is a diagram showing an example of the data structure of the root object. FIG. 11 is a diagram showing an example of a data structure managed by the distributed file management system of the second embodiment. FIG. 12 is a diagram showing a configuration of a creator terminal and an updater terminal of the distributed file management system of the second embodiment. FIG. 13 is a sequence diagram showing a flow of processing for registering the file generated in the second embodiment. FIG. 14 is a sequence diagram showing a flow of processing for registering the updated file in the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
The distributed file management system 100 of the first embodiment shown in FIG. 1 is a decentralized distributed file management system in which terminals belonging to the distributed file management system 100 manage files in a distributed manner. The distributed file management system 100 divides a file into a certain size and manages the file as a directed acyclic graph (DAG) of chunks after the division. The hash value of the DAG root becomes the file ID. By requesting a file using the file ID, the file can be acquired without being aware of the location of the file. The distributed file management system 100 may also manage files in a distributed manner in the same manner as in Non-Patent Document 1.

The distributed file management system 100 of FIG. 1 includes a creator terminal 1, an updater terminal 2, and a file management control terminal 3. The distributed file management system 100 may include a plurality of file management control terminals 3. The terminals belonging to the distributed file management system 100 (creator terminal 1, updater terminal 2, and file management control terminal 3) are connected by P2P (Peer to Peer) via the distributed file management network, and are distributed among the terminals. Manage files. Here, the terminal used by the creator who creates the file is the creator terminal 1, and the terminal used by the updater who updates the file is the updater terminal 2. The creator terminal 1 may update the file, or the updater terminal 2 may create the file. Another terminal may operate as the creator terminal 1 or the updater terminal 2.

(File management data)
The file management in the distributed file management system 100 of the first embodiment will be described with reference to FIGS. 2 and 3.

In the example of FIG. 2, the file F2 which is an update of the file F1 registered in the distributed file management system 100 is registered in the distributed file management system 100.

When the updater terminal 2 registers the file F2 in the distributed file management system 100, the updater terminal 2 takes the difference between the file F1 and the file F2 to generate the difference file D2, and associates the original file F1 before the change with the difference file D2. Generate the root object R2 to be managed. The updater terminal 2 registers the difference file D2 and the root object R2 in the distributed file management system 100.

The root object R2 is an object for acquiring the file F2, and holds a link to the original file F1 and a link to the difference file D2. Specifically, for example, as shown in FIG. 3, the root object has, for each of the original file and the difference file, the type of the linked file and the ID of the file on the distributed file management system 100 (for example, the hash of the file). Use the value), and include the size of the file. The root object contains information about the difference algorithm used to generate the difference file for the difference file. In the distributed file management system 100, the substance of the file can be acquired by using the ID of the file. The root object holds the ID of the file as a link to the file.

In the present embodiment, the ID of the root object R2 registered in the distributed file management system 100 is treated as the ID of the updated file F2. If the ID of the root object R2 is known, the file F2 can be acquired. When a terminal belonging to the distributed file management system 100 (either the creator terminal 1, the updater terminal 2, or the file management control terminal 3) acquires the file F2, the distributed file management system uses the ID of the root object R2. Acquire the root object R2 from 100. The terminal acquires the original file F1 and the difference file D2 from the distributed file management system 100 by using the ID of the original file and the ID of the difference file held by the root object R2. The terminal obtains the file F2 by applying the difference file D2 to the original file F1.

Regarding the original file F1, the root object R1 that holds the link to the original file F1 may be registered in the distributed file management system 100, and the ID of the root object R1 may be treated as the ID of the original file F1.

FIG. 4 shows an example of various files registered in the distributed file management system 100 when the update is repeated. In the example of FIG. 4, the distributed file management system 100 includes the root object R2 and the difference file D2 of the original file F1 and the file F2 in which the original file F1 is updated, and the root object R3 and the difference file D3 of the file F3 in which the file F2 is updated. , The root object R4 and the difference file D4 of the file F4 which updated the file F3, and the root object R5 and the difference file D5 of the file F5 which updated the file F2 are registered.

When registering the file F3 obtained by updating the file F2 in the distributed file management system 100, the updater terminal 2 creates a distributed file of the difference file D3 between the file F2 and the file F3 and the root object R3 that links the file F2 and the difference file D3. Register with the management system 100. The link destination of the original file of the root object R3 is the root object R2 of the file F2.

When it is desired to acquire the file F3, the terminal acquires the root object R3 from the distributed file management system 100 by using the ID of the root object R3 of the file F3. The root object R2 is linked to the root object R3 as the original file, and the difference file D3 is linked as the difference file. The terminal acquires the root object R2 and the difference file D3 from the distributed file management system 100 by using the information held by the root object R3. The terminal recursively processes the root object R2 in order to acquire the file F2, and acquires the file F1 and the difference file D2 from the distributed file management system 100 by using the information held by the root object R2. The terminal applies the difference file D2 to the file F1 to obtain the file F2. Then, the terminal applies the difference file D3 to the file F2 to obtain the file F3.

The distributed file management system 100 may provide a function of updating a certain file and confirming the existence of the updated file. This function can be easily realized by using the distributed hash table used to manage the location of files in the distributed file management system. The updater registers the value of the updated root object in the distributed hash table using the root object before the update as a key. A person who wants to confirm the presence or absence of an update can inquire the distributed hash table using the ID of the root object that he / she owns as a key, and can acquire the ID of the root object after the update. By getting the root object and checking its link, you can check that the object is an update object from the root object used in the query key.

(Terminal configuration)
The configuration of the creator terminal 1 and the updater terminal 2 of the first embodiment will be described with reference to FIG.

First, the creator terminal 1 will be described. The creator terminal 1 shown in FIG. 5 includes a distributed file management client 11 and a file creation unit 121.

The distributed file management client 11 includes a distributed file storage unit 111 and a distributed file management control unit 112.

The distributed file storage unit 111 stores files that are distributed and managed by the distributed file management system 100 and information necessary for distributed management. For example, the distributed file storage unit 111 stores chunks in which a file is divided into predetermined sizes, and routing information in which the ID of the file is associated with the identifier of the terminal having the file. The routing information is distributed and stored in each terminal belonging to the distributed file management system 100. By requesting a file from the distributed file management system 100 using the file ID, the terminal can identify the terminal holding the file corresponding to the ID and acquire the file from the terminal.

The distributed file management control unit 112 registers files in the distributed file management system 100, acquires files from the distributed file management system 100, and manages information stored in the distributed file storage unit 111. For example, when registering the file created by the file creation unit 121 in the distributed file management system 100, the distributed file management control unit 112 divides the file into chunks of a predetermined size, collects them in a DAG, and acquires a file ID. .. The distributed file management control unit 112 stores chunks in the distributed file storage unit 111, and notifies the distributed file management system 100 of the file ID and the identifier of the terminal itself. As a result, the distributed file management system 100 knows the terminal that holds the substance of the file specified by the file ID. The distributed file management control unit 112 may notify the distributed file management system 100 of not only the IDs of the root chunks that are the IDs of the files but also the IDs of all the chunks that make up the file.

The file creation unit 121 creates a file. The file creation unit 121 can be configured by a commercially available application that creates a file. The created file may be of any type, for example, a document file, an image file, a music file, or a video file.

Next, the updater terminal 2 will be described. The updater terminal 2 shown in FIG. 5 includes a distributed file management client 21, a file update unit 221, a difference creation unit 222, and a root object creation unit 223.

The distributed file management client 21 includes a distributed file storage unit 211 and a distributed file management control unit 212. The distributed file storage unit 211 and the distributed file management control unit 212 are the same as the distributed file storage unit 111 and the distributed file management control unit 112 of the creator terminal 1.

The file update unit 221 updates the file acquired from the distributed file management system 100. The file update unit 221 can be configured with the same application as the file creation unit 121 of the creator terminal 1.

The difference creation unit 222 generates the original file before the update and the updated file and the difference file updated by the file update unit 221. The difference file may be in any format as long as the updated file can be reconstructed by applying the difference file to the original file. The difference creation unit 222 selects the optimum algorithm from a plurality of algorithms according to the format of the update file and the original file. An algorithm associated with the extension may be set in advance and selected according to the setting, or a difference file may be actually created by a plurality of algorithms and the algorithm with the smallest difference file may be adopted. .. When the difference between the difference file and the update file is small, the distributed file management client 21 may register the update file itself. The difference file is registered in the distributed file management system 100 by the distributed file management client 21.

The root object creation unit 223 generates a root object that links the original file and the difference file registered in the distributed file management system 100. Specifically, the root object creation unit 223 generates a root object including the ID of the original file and the ID of the difference file. Regarding the difference file, the root object creation unit 223 records the information of the difference algorithm used in the root object. When the difference file is the update file itself, the root object creation unit 223 records in the root object that the file associated with the root object is the update file. For example, if there is no description of the difference algorithm, it may be determined that the associated file is not a difference file but an update file. The root object is registered in the distributed file management system 100 by the distributed file management client 21.

The file management control terminal 3 has the same functions as the distributed

file management clients

11 and 21.

Each part included in the creator terminal 1 and the updater terminal 2 may be configured by a computer equipped with an arithmetic processing unit, a storage device, and the like, and the processing of each part may be executed by a program. This program is stored in a storage device included in the creator terminal 1 and the updater terminal 2, and can be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or can be provided through a network.

(File generation)
A process in which the creator terminal 1 generates a file and registers it in the distributed file management system 100 will be described with reference to FIG.

In step S101, the creator terminal 1 creates a file.

In step S102, the creator terminal 1 registers the file in the distributed file management system 100. Specifically, the creator terminal 1 divides the file into chunks to form a DAG, and acquires the ID of the root chunk as the file ID. The distributed file storage unit 111 records the divided chunks and the IDs of those chunks. The creator terminal 1 notifies the terminal belonging to the distributed file management system 100 of the file ID and the identifier of the creator terminal 1.

In step S103, the updater terminal 2 receives the notification of step S102. Other terminals belonging to the distributed file management system 100 may also receive the notification in step S102.

In step S104, the updater terminal 2 stores the routing information in the distributed file storage unit 211 if there is routing information to be held by the updater terminal 2 based on the notified content.

By the above processing, the file created by the creator terminal 1 is registered in the distributed file management system 100. A terminal belonging to the distributed file management system 100 can acquire a file from the distributed file management system 100 by using the file ID.

(Update file)
A process in which the updater terminal 2 updates the file and registers it in the distributed file management system 100 will be described with reference to FIG. 7. It is assumed that the updater terminal 2 has acquired the original file to be updated from the distributed file management system 100.

In step S201, the updater terminal 2 updates the original file.

In step S202, the updater terminal 2 generates a difference file between the original file and the updated file.

In step S203, the updater terminal 2 creates a root object that links the original file and the difference file. For example, the updater terminal 2 creates a root object that holds the ID of the original file and the ID of the difference file. If the difference file has almost the same size as the update file when the difference file is acquired, the update file is linked to the root object together with the original file instead of the difference file.

In step S204, the updater terminal 2 registers the difference file and the root object in the distributed file management system 100. Specifically, the updater terminal 2 obtains the hash value of the difference file and uses it as the ID of the difference file, and obtains the hash value of the root object and uses it as the ID of the root object. The updater terminal 2 divides into chunks if necessary, and stores the difference file and the root object in the distributed file storage unit 211. The updater terminal 2 notifies the terminal belonging to the distributed file management system 100 of the ID of the difference file, the ID of the root object, and the identifier of the updater terminal 2.

In step S205, the creator terminal 1 receives the notification of step S204. Other terminals belonging to the distributed file management system 100 may also receive the notification in step S204.

In step S206, the creator terminal 1 stores the routing information in the distributed file storage unit 111 if there is routing information to be held by the creator terminal 1 based on the notified content.

By the above processing, the updated file of the updater terminal 2 is registered in the distributed file management system 100. The terminal belonging to the distributed file management system 100 can acquire the updated file from the distributed file management system 100 by using the ID of the root object.

As described above, in the distributed file management system 100 of the present embodiment, when the updated file in which the original file is updated is registered in the distributed file management system 100, the difference creation unit 222 sets the original file and the updated file. The difference file is generated, the root object creation unit 223 generates a root object including the ID of the original file and the ID of the difference file, and the distributed file management client 11 registers the difference file and the root object in the distributed file management system 100. As a result, the difference file is registered in the distributed file management system 100 instead of the entire updated file, so that the average file size per file managed by the entire distributed file management system 100 can be reduced.

[Second Embodiment]
The creator terminal 1 and the updater terminal 2 of the second embodiment shown in FIG. 8 belong to the distributed file management system 100 and the blockchain system 200. The distributed file management system 100 is the same as that of the first embodiment.

The blockchain system 200 of FIG. 8 includes a creator terminal 1, an updater terminal 2, and a blockchain control terminal 4. The blockchain system 200 may include a plurality of blockchain control terminals 4. The terminals belonging to the blockchain system 200 (creator terminal 1, updater terminal 2, and blockchain control terminal 4) are connected by P2P via the blockchain network and share blockchain data (distributed ledger) between the terminals. .. The blockchain data is data in which blocks including transactions issued by a terminal belonging to the blockchain system 200 are connected.

In the present embodiment, a contract that manages the ID of the root object for obtaining the file registered in the distributed file management system 100 and the ID of the creator or updater of the file is registered in the blockchain system 200. A contract is a mechanism for executing a program on the blockchain via a transaction. When a transaction for executing a contract is issued, the program is executed when the transaction is grouped into blocks in the blockchain system 200. In the present embodiment, the authenticity of the creator and the updater is ensured by registering the ID of the root object and the information of the creator or the updater of the file that can be acquired from the root object in the blockchain system 200.

(File management data)
File management in the distributed file management system 100 of the second embodiment will be described with reference to FIGS. 9 and 10.

In the second embodiment, the root objects R1 to R5 include links to information files I1 to I5 and identifiers of contracts registered in the blockchain system 200. The information file I1 is a file that holds information about the file. Information about the file includes information about the creation, update, and rights of the file, such as, for example, the creator and updater of the file. The terminal belonging to the blockchain system 200 can access the information registered in the contract by using the identifier of the contract.

When the creator terminal 1 registers the file F1 in the distributed file management system 100, the creator terminal 1 has a link to the file F1 and a link to the information file I1 that holds information about the file F1 (for example, the ID of the creator of the file F1). , The root object R1 including the contract identifier is registered in the distributed file management system 100. The ID of the root object R1 is treated as the ID of the file F1.

As shown in the example of FIG. 10, the root object determines the type of the linked file, the ID of the file on the distributed file management system 100, and the size of the file for each of the original file, the difference file, and the information file. Including. In addition, the root object contains the contract identifier as data.

Note that, as shown in FIG. 11, the contents of the information files I1 to I5 may be included in the root object data.

(Terminal configuration)
The configuration of the creator terminal 1 and the updater terminal 2 of the second embodiment will be described with reference to FIG.

First, the creator terminal 1 will be described. The creator terminal 1 shown in FIG. 12 includes a distributed file management client 11, a file creation unit 121, a root object creation unit 123, and a blockchain client 13.

The distributed file management client 11 and the file creation unit 121 are the same as those in the first embodiment. The file created by the file creation unit 121 is registered in the distributed file management system 100 by the distributed file management client 11.

The root object creation unit 123 generates a root object that holds a link to a file registered in the distributed file management system 100, information about the file, and a contract identifier. The root object is registered in the distributed file management system 100 by the distributed file management client 11.

The root object creation unit 123 may create an information file that holds information about the file, the root object holds a link to the information file, and the distributed file management client 11 may register the information file in the distributed file management system 100. ..

The blockchain client 13 includes a blockchain storage unit 131 and a blockchain control unit 132. The blockchain storage unit 131 stores blockchain data loosely synchronized with all terminals belonging to the blockchain system 200. The blockchain control unit 132 autonomously and decentrally cooperates with the terminals belonging to the blockchain system 200 to maintain the blockchain system. In the present embodiment, the blockchain client 13 registers the ID of the root object and the ID of the creator in the blockchain system 200.

Next, the updater terminal 2 will be described. The updater terminal 2 shown in FIG. 12 includes a distributed file management client 21, a file update unit 221, a difference creation unit 222, a root object creation unit 223, and a blockchain client 23.

The distributed file management client 21, the file update unit 221 and the difference creation unit 222 are the same as those in the first embodiment. The file updated by the file update unit 221 and the difference file generated by the difference creation unit 222 are registered in the distributed file management system 100 by the distributed file management client 21.

The root object creation unit 223 generates a root object that holds a link to the original file, a link to the difference file, information about the updated file, and a contract identifier. The root object is registered in the distributed file management system 100 by the distributed file management client 21.

The root object creation unit 223 creates an information file that holds information about the updated file, the root object holds a link to the information file, and the distributed file management client 21 registers the information file in the distributed file management system 100. You may.

The blockchain client 23 includes a blockchain storage unit 231 and a blockchain control unit 232. The blockchain storage unit 231 and the blockchain control unit 232 are the same as the blockchain storage unit 131 and the blockchain control unit of the creator terminal 1. In the present embodiment, the blockchain client 23 registers the ID of the root object and the ID of the updater in the blockchain system 200. The blockchain client 23 checks whether the ID of the root object of the file acquired from the distributed file management system 100 and the ID of the creator or updater of the file are registered in the blockchain system 200, and the creator of the file. Alternatively, the authenticity of the updater may be confirmed.

The blockchain control terminal 4 has the same functions as the

blockchain clients

13 and 23.

In step S301, the creator terminal 1 creates a file.

In step S302, the creator terminal 1 creates a root object including a file ID, information about the file, and a contract identifier. It is assumed that the contract is registered in the blockchain system 200 and the identifier of the contract is known. The information about the file includes the creator's ID. The creator terminal 1 may create an information file containing information about the file, and may include the ID of the information file in the root object.

In step S303, the creator terminal 1 assigns and registers the ID of the root object of the file created in the contract and the ID of the creator. The creator terminal 1 may further assign the ID of the updater who permits the update of the file to the contract and register it.

In step S304, the creator terminal 1 registers the file and the root object in the distributed file management system 100. Specifically, the creator terminal 1 is divided into chunks if necessary, and the file and the root object are stored in the distributed file storage unit 111, and the file ID, the root object ID, and the creator terminal 1 are stored. Notify the terminal belonging to the distributed file management system 100 of the identifier.

In step S305, the updater terminal 2 receives the notification of step S304.

In step S306, the updater terminal 2 stores the routing information in the distributed file storage unit 211 if there is routing information to be held by the updater terminal 2 based on the notified content.

By the above processing, the file created by the creator terminal 1 is registered in the distributed file management system 100. A terminal belonging to the distributed file management system 100 can acquire a file from the distributed file management system 100 by using the ID of the root object of the file. The authenticity of the creator can be confirmed by checking that the ID of the root object and the ID of the creator are registered in the blockchain system 200.

(Update file)
A process in which the updater terminal 2 updates the file and registers it in the distributed file management system 100 will be described with reference to FIG. It is assumed that the updater terminal 2 has acquired the original file to be updated from the distributed file management system 100.

In step S401, the updater terminal 2 updates the original file.

In step S402, the updater terminal 2 generates a difference file between the original file and the updated file.

In step S403, the updater terminal 2 creates a root object including the ID of the original file, the ID of the difference file, the information about the updated file, and the identifier of the contract. The contract identifier can be found from the root object of the original file. The information about the file includes the updater's ID. The updater terminal 2 may create an information file containing information about the updated file and include the ID of the information file in the root object.

In step S404, the updater terminal 2 assigns the ID of the root object of the updated file and the ID of the updater to the contract and registers it. Here, if the root object ID and the updater ID cannot be registered due to the contract processing, the processing after step S405 may be stopped. For example, if the updater terminal 2 does not have the right to update the original file, the registration of the root object ID and the updater ID is rejected in the contract process.

In step S405, the updater terminal 2 registers the difference file and the root object in the distributed file management system 100. Specifically, the updater terminal 2 is divided into chunks if necessary, and the difference file and the root object are stored in the distributed file storage unit 111, and the difference file ID, the root object ID, and the updater terminal are stored. Notify the terminal belonging to the distributed file management system 100 of the identifier of 2.

In step S406, the creator terminal 1 receives the notification of step S405.

In step S407, the creator terminal 1 stores the routing information in the distributed file storage unit 111 if there is routing information to be held by the creator terminal 1 based on the notified content.

By the above processing, the updated file of the updater terminal 2 is registered in the distributed file management system 100. The terminal belonging to the distributed file management system 100 can acquire the updated file from the distributed file management system 100 by using the ID of the root object of the updated file.

A terminal belonging to both the distributed file management system 100 and the blockchain system 200 obtains the updater ID and the contract identifier from the root object acquired from the distributed file management system 100, and obtains the updater ID and the root object in the contract. The authenticity of the updater can be confirmed by checking whether or not the ID is registered.

As described above, according to the present embodiment, the root object creation unit 223 generates a root object that holds the updater ID and the contract identifier, and the blockchain client 23 sets the contract with the root object ID. By registering the updater's ID, it is possible to confirm the authenticity of the updater by checking that the root object ID and the updater's ID are registered in the blockchain system 200.

1 ... Creator terminal 11 ... Distributed file management client 111 ... Distributed file storage unit 112 ... Distributed file management control unit 121 ... File creation unit 123 ... Root object creation unit 13 ... Blockchain client 131 ... Blockchain storage unit 132 ... Blockchain Control unit 2 ... Updater terminal 21 ... Distributed file management client 211 ... Distributed file storage unit 212 ... Distributed file management control unit 221 ... File update unit 222 ... Difference creation unit 223 ... Root object creation unit 23 ... Blockchain client 231 ... Block Chain storage unit 232 ... Blockchain control unit 3 ... File management control terminal 4 ... Blockchain control terminal 100 ... Distributed file management system 200 ... Blockchain system

Claims

An update device that registers an update file that updates the original file registered in the distributed file management system in the distributed file management system.
A difference generator that generates difference data between the original file and the update file,
A route object generation unit that generates a route object including a link to the original file and a link to the difference data, and
An update device including a file management control unit that registers the difference data and the root object in the distributed file management system.
The renewal device according to claim 1.
The update device, characterized in that the link to the original file is a link to the root object of another update file.
The renewal device according to claim 1 or 2.
The update device, characterized in that the root object contains information on the algorithm used to generate the difference data.
The renewal device according to any one of claims 1 to 3.
The update device belongs to the distributed ledger system,
The root object contains information about the update file and an identifier of a contract executed in the distributed ledger system.
An update device including a registration unit for registering information about the update file and a link to the root object in the contract.
This is an update method using an update device that registers an update file that updates the original file registered in the distributed file management system in the distributed file management system.
Steps to generate difference data between the original file and the update file,
A step of generating a root object containing a link to the original file and a link to the difference data,
An update method comprising the step of registering the difference data and the root object in the distributed file management system.
An update program that operates a computer as each part of the update device according to any one of claims 1 to 4.
The data structure of the update file that updated the original file
The link to the original file and
Includes a link to the difference data between the original file and the update file.
If the original file is another update file, the link to the original file is a link to the data structure of the other update file.
In a process in which a computer acquires the original file from a link to the original file, acquires the difference data from the link to the difference data, applies the difference data to the original file, and acquires the update file. When used and the link to the original file is a link to a data structure to the other update file, the computer is characterized in that it recursively processes the data structure of the other update file. data structure.
The data structure according to claim 7.
Information about the update file and
Including the identifier of the contract executed in the distributed ledger system,
A data structure characterized in that the computer belonging to the distributed ledger system is used in a process of checking whether or not information about the update file and a link to the data structure are registered in the contract.